A beacon illuminates a key Alzheimer's protein

Researchers can now see tau, which accompanies amyloid in diseased brains

BEACON OF TAU In a PET scan, the protein tau is illuminated (left) in the hippocampus (arrowhead) of a brain of a person suspected to have Alzheimer's disease. A scan that reveals amyloid (right) shows a slightly different pattern.

Deep within the living brain, a newly created beacon can illuminate hidden signs of Alzheimer’s disease.

Recent work has focused on detecting amyloid, a sticky substance that builds up in the brains of people living with Alzheimer’s. But until now, clinicians lacked a good way to see amyloid’s co-conspirator, the protein called tau. Tangles of a harmful form of tau pile up inside the brains of people with Alzheimer’s disease and several other dementias.

Masahiro Maruyama of the National Institute of Radiological Sciences in Japan and colleagues report September 18 in Neuron that a class of molecules can latch on to tau tangles. When linked to radioactive carbon, these molecules serve as beacons that illuminate tau during PET scans.

Scientists know from work with cadavers that the hippocampus harbors tau as Alzheimer’s disease progresses. The new imaging tool will help scientists diagnose and study Alzheimer’s disease and other disorders marked by tau accumulation in living people, the researchers write.